Effect of tortoise oligopeptides on cyclophosphamide-induced leukopenia

Cyclophosphamide is a nitrogen mustard derivative that becomes active through hydrolysis by excessive cytochrome P450 enzymes or phosphatases in the liver or tumor, transforming into its active form. It has a broad anti-tumor spectrum and is the first so-called "pro-drug" with broad-spectrum anti-cancer activity, effective against both leukemia and solid tumors. Bone marrow suppression is a common adverse effect of cyclophosphamide, often presenting as neutropenia. Currently, the primary treatment for cyclophosphamide-induced neutropenia is recombinant human granulocyte colony-stimulating factor (rhG-CSF) injections. However, this medication can only be used after chemotherapy-induced leukopenia occurs, making it ineffective for preemptive intervention against cyclophosphamide-induced neutropenia. Moreover, while rhG-CSF stimulates bone marrow to produce blood cells, it may also promote the growth of cancer cells. Therefore, we aimed to develop a safe and effective food product to improve cyclophosphamide-induced leukopenia.We analyzed the physical properties, nutritional content, peptide molecular weight distribution, and amino acid composition of tortoise oligopeptides to monitor their quality and ensure experimental reproducibility. Building on this foundation, we conducted animal experiments and found that tortoise oligopeptides can ameliorate cyclophosphamide-induced leukopenia in mouse models. The mechanism primarily involves the improvement of pathological damage in the spleen and femur and the modulation of serum immune factors such as TNF-α, IFN-γ, IL-1β, and IL-4. To further investigate whether tortoise oligopeptides influence the chemotherapy effects of cyclophosphamide on tumors, we created tumor-bearing mouse models using S180 cells. We discovered that tortoise oligopeptides exhibit a synergistic effect that enhances efficacy and reduces toxicity in mice undergoing cyclophosphamide chemotherapy. Additionally, we found that tortoise oligopeptides can regulate gut microbiota. KEGG analysis indicated a correlation between changes in gut microbiota and immune diseases. We conducted a correlation analysis of the significantly different microbial taxa among groups and the tumor and immune data of tumor-bearing mice to explore the possible mechanisms behind the enhanced efficacy and reduced toxicity of tortoise oligopeptides during cyclophosphamide chemotherapy.This study provides experimental evidence for the use of tortoise oligopeptides as a dietary intervention for cyclophosphamide-induced leukopenia. We explored the mechanisms by which tortoise oligopeptides elevate white blood cell levels from the perspectives of immunity and gut microbiota. Our study will significantly contribute to the literature and be of interest to your readership, as we investigated the effects of tortoise oligopeptides as food on leukopenia from both gut microbiota and immunological perspectives.